Outbound Trip 120 miles 60 mph equals 2 hours
Return Trip 120 miles
Total Trip 240 miles at 45 mph average speed
Total time = distance / rate = 240 / 45 = 5.3333333333 Hours
The return trip of 120 miles takes (5.3333333333 Hours MINUS 2 hours)
Return Trip Speed = 120 / 3.333333333 = 36 miles per hour